In this paper, we first develop a delay-dependent condition for the stability and Hinfin performance of systems with time-variant delays in both the state and output equations in terms of an LMI (linear matrix inequality). The analysis result is then applied to derive a Hinfin congestion control where the congestion problem is formulated as the Hinfin control of systems with time-variant input delays. Illustrative examples are provided to show excellent performance of the proposed algorithm in achieving an equilibrium in the buffer occupancy in the presence of time-variant delays. To the best of our knowledge, no such congestion control approach that directly accommodates the issue of the uncertain time-variant delays has been reported